In this paper we present, simulate, and evaluate Dynamic Asynchronous Neighbor Discovery protocol for Directional Antennas (DANDi), a neighbor discovery protocol for Wireless Sensor Networks (WSN) with directional antennas that guarantees that every reliable communication link in a network is discovered. DANDi is asynchronous, fully directional (supports both directional transmissions and receptions) and has a dynamic contention resolution mechanism based on the detection of packet collisions, so no network topology information is needed in advance. We propose, implement and evaluate a mechanism to identify these collisions, both in simulations and with real nodes. DANDi is implemented in Contiki OS, an open-source operating system for WSN and the Internet of Things, and extensively tested. First using the COOJA network simulator and then with real Tmote Sky nodes equipped with 6-sectored antennas. The neighbor discovery times are analyzed and analytical expressions for these times are presented. The DANDi protocol performance is compared with Sectored-Antenna Neighbor Discovery, a state-of-the-art protocol for this kind of networks. Our experiments show that the discovery time can be reduced up to four times in average depending on the network topology, while discovering every reliable sector-to-sector link. To the best of our knowledge, DANDi is the fastest protocol that is able to discover every reliable link in a network without requiring any prior information of the network topology.

在本文中，我们提出、模拟和评估定向天线动态异步邻居发现协议 (DANDi)，这是一种用于具有定向天线的无线传感器网络 (WSN) 的邻居发现协议，可确保发现网络中的每个可靠通信链路。 DANDi 是异步的、完全定向的（支持定向发送和接收），并具有基于数据包冲突检测的动态争用解决机制，因此不需要提前提供网络拓扑信息。我们提出、实施和评估一种机制来识别这些冲突，无论是在模拟中还是在真实节点中。 DANDi 在 Contiki OS 中实现，Contiki OS 是一个用于 WSN 和物联网的开源操作系统，并经过了广泛的测试。首先使用 COOJA 网络模拟器，然后使用配备 6 扇区天线的真实 Tmote Sky 节点。分析了邻居发现时间并给出了这些时间的解析表达式。 DANDi 协议性能与扇形天线邻居发现（此类网络的最先进协议）进行了比较。我们的实验表明，根据网络拓扑，发现时间平均可减少四倍，同时发现每个可靠的扇区到扇区链路。据我们所知，DANDi 是最快的协议，能够发现网络中的每个可靠链路，而无需任何网络拓扑的先验信息。